Joint arthroplasties can be highly invasive and often require surgical resection of the entirety, or a majority of the, articular surface of one or more bones involved in the repair. In various procedures, the marrow space can be fairly extensively reamed in order to fit the stem of the prosthesis within the bone. Reaming results in a loss of the patient's bone stock and over time subsequent osteolysis will frequently lead to loosening of the prosthesis. Further, the area where the implant and the bone mate can degrade over time requiring the prosthesis to eventually be replaced. Since the patient's bone stock is limited, the number of possible replacement surgeries is also limited for joint arthroplasty. In short, over the course of 15 to 20 years, and in some cases even shorter time periods, the patient can run out of therapeutic options ultimately resulting in a painful, non-functional joint and/or requiring fusion or partial-fusion of the joint.
Current joint replacement and/or resurfacing implants, and the surgical corrections associated with implanting such devices, are generally accepted to be of finite duration. That is, assuming the patient's continued survival and/or continued use of the joint, every joint replacement and/or repair procedure will eventually require further surgery to repair and/or replace a failed or failing joint implant.
Failure of an implant and/or surgical correction can be a result of various causes. The implant may fracture, loosen or disassemble in some manner, or components may simply wear out and/or cease to properly function after prolonged use. Similarly, implant failure may be due to failure of the underlying support and/or anchoring structures, either due to continued progression of disease or pursuant to unexpected and/or excessive stresses. Moreover, an implant may fail where it has been malpositioned, or where it is experiencing unexpected/unacceptable loading for a variety of factors. Another contributing failure factor could be excessive pain generated and/or felt at the implant site. Other failure factors can include excessive debris generation, scar tissue intrusion into the joint space and/or unacceptable inflammation/swelling of the joint, uncontrollable infection at the implant site, and or development of necrosis, cysts, malignant neoplasm or other localized or systemic disease necessitating implant removal.
Regardless of the underlying cause, the removal of a failed implant generally necessitates a surgical intervention to remove or otherwise revise the original “failed” implant. Such a procedure also typically involves the placement of a subsequent or “revision” implant in the joint space, to correct the underlying joint function and/or otherwise address additional hard and soft tissue damage that may have occurred during the initial implant removal process and/or during subsequent preparation and placement of the revision implant. However, because a significant and potentially unknown amount of the original anatomical support structure is generally removed during the original implant surgery to place the original implant (now failed or failing), because additional native support structures may be removed with the failed implant, because the amount of further degradation of the anatomical support structure (post original surgery) is generally unknown or undetermined prior to removal of the failed implant during the revision surgery and because “artifacts” from the failed or failing implant often distort or otherwise mask anatomical or other features obtained using non-invasive imaging methods, there remains a significant need for improvements in the planning and execution of revision surgeries.